Not uncommon with at least the aging population and many others are medical and physiological conditions such as acquired central and neural foraminal stenosis. It has been estimated by some that by the year 2030, approximately 45% to 50% of the population will be 65 or greater and with increased population age the condition of spinal stenosis and its clinical presentation of neurogenic claudication may continue to grow. Traditional treatment options include performing decompressive laminectomies, partial medial facetectomies, and/or partial foraminotomies in order to gain adequate decompression. Such procedures tend to result in some level of iatrogenic instability into the motion segments involved.
Other traditional treatment options may include fusion technology such as pedicle screw or segmental instrumentation posteriorly and/or interbody techniques such as posterior lumbar interbody fusion, lateral interbody fusion technology, TLIF (transforaminal interbody fusion), XLIF (extreme lateral interbody fusion), ALIF (anterior lumbar interbody fusion), DLIF (direct lateral interbody fusion), or GLIF, a perilinear approach to the anterolateral interbody region exists. These technologies, coupled with bone graft materials for fusion including, but not limited to, autologous bone, allograft bone, demineralized bone, bone morphogenetic proteins, growth factors, cement, gene therapy, and/or mesenchymal stem cells, have become more and more prevalent. Limited interbody fusion techniques such as interbody spacers that are capable of fusing one spinous process to the other, facet screws, facet bolts, or stand-alone cages may be used with a certain degree of bone graft material to allow the motion segment to be fused. Multilevel decompressions and fusions also are known to carry with them a greater risk for nonunion or pseudoarthrosis because of the number of motion segments attempting to be fused.
In the case of spinal stenosis pressure (compression) on the nerve, dura or thecal sac can lead to pain and discomfort which may limit walking, bending and deteriorate the quality of life. Pain and discomfort may also lead to the use of and narcotics, anti-inflammatory medications, muscle relaxers, epidural steroid injections, and physical therapy.
FIG. 1 illustrates a traditional surgical drill which may be used to treat the spinal canal. One commercially available example of such a device is the Ultrapower™ Surgical Drill System from Hall Surgical. The drill consists of a handpiece 10 connected at its proximal end to a power source, which may, for example, comprise compressed air (not shown). The hand piece 10 has a spindle 12 that rotates in response to actuation of the handpiece motor (not shown), which is driven by the power source. Attached to the front end of the handpiece 10 is a coupling assembly 14. The coupling assembly 14 releasable holds an accessory 16 to the spindle 12 so the accessory 16 rotates in unison with the spindle 12. The accessory 16, having a file, rasp or burr 18 at its distal end, is releasably coupled to a handpiece spindle 12. The cutting accessory 16 has a shaft 20, the proximal or rear end of which is releasably held to the spindle 12 by the coupling assembly 14.
The cutting accessory 16 typically stands past the distal tip of the surgical device 22. In this position, it is possible that the file, burr or rasp 18 could cause unintended injury. For example, because of the power of the tool, it is possible that the dura could be pulled into the working channel of the file, burr or rasp or other resecting instrument. If the neural tissue were pulled into the surgical drill, a neurologic catastrophe could result.